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J. M. LAIHO March 4, 1952 INTERLOCK FOR CALCULATING MACHINE CONTROL KEYS l2 Sheets-Sheet 5 Original Filed Aug. 8, 1942 March 4, 1952 J. M. LAIHO 2,588,127

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INTERLOCK FOR CALCULATING MACHINE CONTROL KEYS Original Filed Aug. 8, 1942 12 Sheds-Sheet '7 C111: I I I Iii HIIVENTORI ATTOR EYS- March 4, 1952 J. M. LAIHO 2,588,127

INTERLOCK. FOR CALCULATING MACHINE CONTROL KEYS Original Filed Aug. 8, 1942 12 Sheets-Sheet 8 INVENTOR;

J. M. LAIHO March 4, 1952 INTERLOCK FOR CALCULATING MACHINE CONTROL KEYS l2 Sheets-Sheet 9 Original Filed Aug. 8, 1942 INVEN ORI r/a Zm er M. .5 41/10 J. M. LAIHO March 4, 1952 INTERLOCK FOR CALCULATING MACHINE CONTROL KEYS l2 Sheets-Sheet 10 Original Filed Aug. 8, 1942 INVENTORZ (fa 1m e/' M. LEI/lo March 4, 1952 J. M. LAIHO 2,588,127

INTERLOCK FOR CALCULATING MACHINE CONTROL KEYS Original Filed Aug. 8, 1942 12 Sheets-Sheet l1 J. M. LAIHO March 4, 1952 INTERLOCK FOR CALCULATING MACHINE CONTROL KEYS l2 Sheets-Sheet 12 Original Filed Aug. 8, 1942 R O T N E V m Patented Mar. 4, 1952 UNITED STATES PATENT OFFICE INTERLOCK FOR CALCULATING MACHINE CONTROL KEYS Jalmer M. Laiho, Skokie, 111., assignor to Felt & Tarrant Manufacturing Company, Chicago, Ill., a corporation of Illinois 11 Claims. 1

This invention relates in general to calculating machines and has more particular reference to the provision of means for facilitating the use of power-driven, key-responsive machines in negative forms of calculation; namely, subtraction and division, and this application is a division of my co-pending application Serial No. 454,111, filed August 8, 1942, and issued December 2'7, 1949, as United States Patent No. 2,492,703.

A principal object of the invention is to simplify division operations in and with key-responsive calculating machines.

Another important object of the invention is the provision of control means operable to cause the complemental values of a divisor to be automatically entered into the accumulator in division operations.

A further object of the invention is the provision of means in a key-responsive calculating machine for releasing keys depressed in entering the subtrahend which have been retained in depressed position preparatory to a subtractive operation.

An important object of the invention is the provision of a novel mean for preventing the simultaneous depression of a digital control key and a calculation control key.

Another object of the invention is the provision of means in a key-driven or key-responsive calculating machine for preventing the simultaneous depression of a digital control key and the release key and/or operation of the zeroizing levers.

A further object of the invention is the provision of novel means for preventing simultaneous depression of any two calculation control keys.

Numerous other objects and advantages of the invention will be apparent as it is better understood from the following description, which, when taken in connection with the accompanying drawings, discloses a preferred embodiment thereof.

In the accompanying drawings:

Figure l is a top plan view of a calculating machine embodying the invention, showing the .minus. and equals keys and the division key located to the left of the several denominational orders of digital keys;

Figure lAis a top plan view of a single denominational order of keys complementally marked in accordance with the former method of performing negative calculating with key-drivenor keyresponsive calculating machines. g

ij Figure 2 is a longitudinal vertical section taken through the calculating machine shown in Fig. 1 on a plane adjacent a column of digital keys;

Figure E is a longitudinal vertical section taken through the calculating machine of Fig. 1, on a plane adjacent the overflow column and showing the digital control shifting mechanism and details of the accumulator mechanism;

Figure '4 is a longitudinal vertical section also taken at the left side of the calculating machine shown in Fig.1, and showing the subtraction and division control mechanism;

Figures 5, Band 7 are detail views of the digital actuation control mechanism;

Figure 8 is a detail view showing the construction of the digital control bar, taken along the line8 -8 of Fig. 6;

' Figure 9 is a transverse section taken at the rear of the machine and looking toward the front thereof, with certain parts omitted to show details of the division control mechanism when the machine is set for additive actuation;

Figure 10 is a similar view showing the division control mechanism when the machine is set for divisive operation;

' Figure 11 is a top plan view, broken away centrally from front to back, of the calculating machine shown in Fig. 1, showing details of the arrangement of the digital actuation control mechanism and shifting means;

Figure 12 is a perspective view of the overlapping means for causing automatic actuation of all denominational orders where no keys are depressed to the right of the key representing the leftmost or highest order figure of the divisor which is depressed in entering the divisor during a divisive operation;

Figure 13 is a top plan view of the latch means for preventing relatching of the power trip mechanism and digit control keys in depressed position after a power action has taken place;

Figure 14 is a perspective view of the said latch;

Figure 15 is a longitudinal vertical section of the calculating machine shown in Fig. 1 taken at the right side of the machine and showing the release keys and'zeroizing crank;

Figiue 16 is an enlarged view showing details of part of the interlocking mechanism;

Figure 17 is a front elevation of the mechanism shown in Fig. 16 taken on the line l'l--I'I of Fig. 16; V a .1 Figure 18 is an enlarged view showing some parts of the mechanism of. Fig..16 in changed position, and with parts broken away;

Fig. 19 is a view showing a supplemental key release mechanism;

- Figure 20 is a perspective view of a modification of the supplemental key release mechanism employed in a single order of the machine in order to clear certain parts which obstruct and prevent the use of the key-release mechanism of Fig. 19 in that order;

Figure 21 is a side elevation of part ofthe interlocking mechanism associated with the control keys at the left hand side of the machine;

Figure 22 is a rear view of the mechanism shown in Fig. 21 taken on the line 2222 of Fig. 1 and drawn at a different scale Figure 23 is a front view of the mechanism shown in Fig. 21 taken on the line 23-23 of Fig. 21.

For the purpose of illustrating my invention, I have shown in the drawings a key-responsive, power-driven calculating machine similar to that shown and described in Patent No. 2,063,962,

denominational order for each tens transfer that is to be eli'ected. The carrying-cam member 36 acts upon a dolly roll secured to a bell-crank carrying-lever (not shown) to swing the latter in a clockwise direction, viewing Fig. 3. Such swinging of the carrying-lever causes a carrying pawl 4| pivotally mounted on said lever to throw issued December 15, 1936, with some changes as shown in United States Letters Patent .No. 2,018,933, issued October 29, 1935, and with improvements illustrated, described and claimed drawings, the calculating machine is shown as having an outer casing ZIwithin which the various instrumentalities of the machine are mounted on skeleton frame members or partition plates 22 disposed between the actuating mechanisms of the several denominational orders and secured together in spaced relationship at suitable points by tie-rods 23. A plurality of columns of digital keys'24, normally held in raised position by means of'springs 38, are arranged to extend through a keyboard 25, positioned as part of the upper wall of the casing 2|, which keys are adapted for manipulation to determine the digital degree of actuation to be imparted to the different denominational orders of accumulator mechanism. Each column of keys 24 controls the rotation of an accumulator actuating pinion 26 (Fig. 3) journaled upon a transverse shaft 27 that extends across the machine and is supported by the frame members 22. Rotation of each of the actuating pinions 26 is transmitted through an internal ratchet mechanism to a combined lantern wheel and accumulator gear 28 (Fi 3) which is also journaled on the shaft 27. The gear of each of the lantern wheels 28 meshes with a carrying gear 30 journaled on a shaft 29 (Fig. 3), which is disposed in parallel relationship to the shaft 27. The carrying gears also respectively mesh with intermediate gears 31 journaled on a transverse shaft 32, eachv of which in turn meshes with a numeral wheel pinion 33 journaled on a trans.- verse shaft 34 and fixed to a numeral wheel 35 (Fig. 3).

Carrying mechanism is provided in each denominational order of the accumulator mechanism for the purpose of imparting a, digital unit of actuation thereto each time that a tens transfer is to take place from the next lower denominational order of the accumulator. This mechathe lantern wheel and accumulator gear 28 a suffi'cient distance to impart, through the train of .gear sections 42 (Fig. 3) which are in mesh with the pinions 26, a said sector being associated with each denominational section of the accumulator unit in association with its controlling column of keys. The gear sectors and the control and actuating mechanism for them are duplicated for each denominational order of the calculating machine, and a general description of a single set of such mechanism will be sufficien-t for an understanding of them all, except that they have to be arranged and adapted to cooperate selectively and collectively with the power members.

The gear sectors 42 are mounted upon a shaft 43 which extends through the partition plates 22 of the machine, and are adapted to be moved downwardly (viewing Figs. 2, 3 and 4) on an idle or setting stroke in amount determined by the value of the particular digital key 24 of the associated column depressed, this amount increasing in graduating steps from 1 to 9. The keys 24 in addition act through a power trip mecha-' nism to effect a connection whereby power supplied by an electric motor, indicated generally at 44 (Fig. 3), through a power shaft 45, which is connected to the motor in any suitable manner, is eliective to extend a spring 46 associated with the particular order of mechanism with which the key depressed is identified. Release of this spring thereafter accomplishes adding movement in amount determined by the particular digital key of the order depressed. Upon depression of said key, the gear sector 42 is moved through its idle or downward stroke by the power shaft 45 into position to impart proper and accurate nism, as well as that hereinbefore described, is

member 36 (Fig. 3), which isgivena 180 rotation by a suitably carrying, motor spring 37 associated with a carrying gear of the next lower digital accumulation to the adding mechanism upon its return movement, which is accomplished by the associated spring 46.

- In the calculating machine shown in the drawings, depression of a key 24 causes its stem 4'! (Fig. 2) to engage a parallel motion bar 43 which is pivoted at the front at 49 and at the rear at 5| to levers 52 and 53, respectively, which levers are pivoted in turn upon cross shafts or rods 54 and 54' extending through the partition plates 22. A link 55 is pivotally connected at 56 to the lever 52 and at '57 to the lever 53. The bar 48, levers 52 and 53 and the link 55 form part of a parallel motion device, and are constructed and mounted as shown and described in United States Letters Patent No. 2,063,962, earlier mentioned. Further and more particular description of these of these parts is therefore thought to be unnecessary. Each of the gear sectors 42, as stated above, is pivoted upon the cross shaft 43, and through a yielding clutch 93 is articulately con.- nected to a, hook 58 by a link 59 (the hook 58 and link 59 being articulately connected to a vertical guide member 60 which in turn is pivotally mounted on a shaft 50). Each gear sector 42 is also articulately connected to a movement controlling bar, generally shown at 6|, by apin 62 securely fixed to an arm 39 of the gear sector 42 (Fig. 3), as will be later described in detail. A spring 64 attached to lever 53 and to a tail piece 65 of a latch member 66 carried by the bar normally contributes toward holding the parallel motion device in elevated position for a purpose which will be presently explained. A dog 61 which is pivoted at 68 on the parallel motion bar 48 is provided with a laterally and downwardly extending lug 69, which is adapted for engage ment wtih" a lug or 1shelf H on a spring-lifted lever 12 pivotally mounted on the guide member 69 with the hook 58. The operation of the parts is such that upon depression of a key 24, the stem 41 engages and depresses bar 48, imparting motion to the parallel motion device; which carries dog 61' downwardly to depress lever 12. A spring mounted on the pivot between the link 59 and the hook 58 engages the'lever 12 and the hook to urge the rear end of the latter downwardly, so thatit will normally cause engage- I ment of the hook 58 with a toothed wheel 13 upon depression of lever 12. However, this spring connection between hook 58 and lever 12 will permit movement of the latter by the dog 61 relative to the hook, if the hook is restrained in its normal raised position of Figs. 2 and 4 in a manner to be later described. The toothed wheel 13 is fastened to the power shaft 45, which continually turns in a counter-clockwise direction. The engagement of the hook 58 with the wheel 13 pulls the link 59 toward the rear of the machine, or toward the left, viewing Figs. 2 and 3, which imparts downward motion to gear sector 42, through the yielding clutch 63. Forward motion is thus imparted to the digital control bar 6|, until one of several lugs projecting ver- ,tically therefrom, as will be hereafter more fully explained, is stopped by the stem 4'! of the key 24 depressed.

The rearward motion of hook 58 and link 59,

which are articulately connected to each other and to guide arm 60, causes said guide arm to pivot in a counter-clockwise direction about its shaft 50 to extend spring 46, one end of which is connected to the guide arm and the other end to a shaft or rod extending through partition plates 22. The link 59 moves the gear sector 42 downwardly on an idle stroke and into position to impart an adding movement upon release of the hook 58 and contraction of the spring 46.

The downward movement of the gear sector 42 is under the control of the digital control bar 6| (Fig. 3), and the gear sector is halted when it has been moved downwardly the proper distance, enabling it upon return to impart the degree of digital advancement to the adding mechanism :which corresponds to the particular key depressed. The yielding clutch 63 permits the continuation of the rearward movement of the link 59 after downward movement of the gear sector 42 has been stopped, and until the end of the power stroke and the automatic release of the hook 58. The release of the hook 58 is accomplished automatically in each instance after a set increment of action has been imparted to the link 59, by the teeth of the wheel 13. Upon the return stroke (the operative stroke of the gear sector), the yielding clutch 63 permits relative 'fznovementof the parts in reverse direction to the beginning of the adding movement, and thereafter the adding actuation is accomplished.

It is apparent, therefore, that upon depression of a key 24, the digital control bar 6| determines the degree and extent of the downward movement of the gear sector 42,- and the bar 48 accomplishes connection of the latter to the power mechanism. Means are provided to prevent return movement of the dog 61 before the hook 58 has opportunity to fully engage the toothed wheel, which means comprise latch member 66 which is pivoted at 14 on link 55. This latch member has an engaging arm 75 which is adapted to engage upon the laterally projecting end 16 of the dog 61 to hold the dog down against return upward movement and the parallel motion device in depressed position. Just prior to the release of the hook 58, a pin 1! in an upwardly extending arm 18.01 vertical guide member 60 which, through its connection with hook 58 has been carried rearward.- ly, engages a finger 19 of latch 66 and frees the dog 6'! so that the parallel motion device may return to normal raised position. However, if a digit key is held prolongedly in depressed position thereby preventing therising of parallel motion bar 48 and dog 61, then means must be provided to assure the continued disengagement of latch 66 and dog 67. Upon the return or forward motion of hook 58, the horizontal shelf ll of lever '12 engages the lug 69 of dog 61 to rock the dog counter-clockwise to prevent the re-engagement of arm 15 of latch 66 with lug..'|6 of dog 61 so that upon subsequent release of the digit key all the parts can return to normal position. A bar 8| having rearwardly extended pointed locking lugs or teeth 82, is pivoted upon studs 83 and 83 extending through slots 84. and 84' in bars 48 in each denominationalorder of the machine, said studs 83 and 83 being secured to bracket levers 52 and 53 respectively. Consequently, upon depression of a key 24, bar 8| is moved rearwardly (to the left viewing Fig. 2), relative to key stems 41. Referring more particularly to Figs. 9 and 10, each key stem is provided adjacent its lower end with an aperture 85 extending therethrough into which the. tooth 82 enters in the'rearward movement of the bar 8|, thus holding the key down until the parallel motion device is'released and the parts returned to normal elevated position. It will be understood that, while no two keys 24 of the same column or denominational order may be operated simultaneously, as described in Patent No. 2,043,021 issued June 2, 1936, any key of one order may be operated at the same time as any desired key of any other denominational order or orders.

In the machine in which the present invention is embodied, subtraction is performed in accordance with the method and means fully. described .of the parallel motion bars 48 earlier described. :Depression of the minus control key 86 and parallel motion bar 89 causes forward movement (to the right viewing Fig. 4) of a link 255, and allows latch member 266 to engage a dog 26'! to hold the parallel motion bar in depressed position. The key 86 is also maintained in depressed position by a-tooth 9| formed on a bar 92 which is moved rearwardly upon depression of key 86, allowing tooth 9| to enter an aperture 285 in the keystemjfi. ,Subsequent to depressionof the Iftiiinus control key 86, the keys representing the subtrahend are depressed and maintained in such depressed position until the equals control key is depressed whereupon the adding actuation which was not immediately responsive to depression of the digit keys is allowed to take place and the keys returned to normal elevated position. with ajvertical projection 93 adapted normally to underlie the stem 88 of the equals key 81 to prevent depression of the latter until the minus i The bar 92 also is prov ded key 86 has been depressed. Upon depression of j the minus control key 86, its stem 88 engages an upwardly extending arm 94 (Fig. 4) of a lever 95 which is also provided with a downwardly and forwardly extending arm 96 and is pivoted at '9'!" on a pin fixed to an intermediate plate 22. To

the lower end of the lever 95 is pivoted a pawl 98 which is provided with a downwardly extending arm 99, a rearwardly extending horizontalv arm IIII, and an upwardly extending arm I02." The lower arm 99 is normally positioned above a pin I05 in an arm I66 which is securely fastened'- Securely fas-*' tened to the shaft I01 are lock arms I08 (Figs.{ 2 and 3), one for each denominational order of the machine, each of which is provided with a laterally extending lug I09 adapted, upon de-k to a transverse rock shaft IllI.

of such setting of the lock arms I08 into engagement with the lugs III of hook members 58 by depression of the minus control key 86, subsequently depressed digit keys 24 also are caused to be latched in depressed position by engagement of the teeth 82 in their apertures 85, the associated parallel motion mechanisms being heldin lowered position by engagement of dogs 61 by their associated latches 66.

The digital actuation of the adding mechanism is automatically controlled in accordance with the nines complemental value of the keys depressed in entering a subtrahend in all denominational orders except the units order, in which the tens complemental value of the key depressed is added. The mechanism controlling the digital actuation of the adding mechanism in each denominational order is indicated enerally at 6| (Fig. 6') and comprises a regular stopbar I I2 and a complemental stop bar I I3, secured together and spaced relative to each other by means of studs H4 (Figs. 5 and 8).. The bars 'I I2 and H3 have formed thereon verticallyprojecting stop lugs I I 5, the lugs II 5 of the stop bar I I2 being spaced progressively further. backof the key stems from the front to the rear of the machine, and the lugs II5 of stop bar II3 being spaced progressively further back of the key rearmost lug is spaced nine steps back of the 9- key. The stop lug of the complemental stop bar I I3 just to the rear of the I key is spaced eight steps back of the 1 key and the spacing graduatedly decreases until the lug back of the 8 key is spaced one step therefrom and the last stop lug is just even with the 9 key.

It has been earlier explained that in machines of this type it has been the necessary practice in entering the subtrahend to enter one less in the units order or, in other words, to strike the nines complement of all orders except the units order, in which the tens complement was entered to obtain the correct result. The means for controlling the digital actuation of the accumulator mechanism in the units order in accordance with the tens complement of the key depressed or, if no ke has been depressed, to automatically add 10 in such order to bring about the correct result, is accomplished by an arrangement or spacing of the stops on the tens complemental stop bar I I3 of the units order (as shown in Fig. 7), diiferent from that of the nines complemental stop bar I I3 in all other orders. In other words the stops II5 on' the tens complemental stop bar N3 of the movement controlling bar 6I in the units order (Figs. 5 and '7) are spaced progressively one step further back than are the stops II5 on the nines complemental stop bars H3. The gear sector in the units order therefore is given a relatively greater adding movement by the tens complemental stop bar II3. than are the gear sectors of all other higher denominational orders under the control of their complemental stop bars H3. The complemental stop bars H3 and H3 are provided at their forward ends with depending arms I I6 having a bifurcated portion adapted to embrace the pin 62 located in the upwardly extending arm 39 of the associated gear sector G2 (Fig. 3).

Means are provided, when desiring to enter the complement of the subtrahend during a subtractive operation, for shifting the complemental stop bars H3 and H3 into operative relation with the ordinal series of keys, so that upon depression of a key and subsequent downward movement of the gear sector 42, the complemental value of the key depressed will be added into the accumulator, as distinguished from the actual value of the key depressed when the regular stop bar I I2 is in operative relation therewith. The lower portion of stem 88 of the subtraction control minus key 88 is provided with an angular surface in engagement with a roll H8 which is rotatably secured to an upright arm H9 (viewing Fig. 3), which in turn is fixedly secured to a longitudinal rock shaft I2! having a bearing in vertical support pieces I i? and Ill" which are supported on tie rods 23. Also securely fixed to the rock shaft I2I are upright arms I23 and I2 3, located at the front and rear of the machine, respectively, (Fig. 3). The upper free portion of the arm I23 is disposed in a small slotted portion I26 of a transverse support bar I25 positioned near the front ofthe machine (Figs. 3, 5 and 11), which is slidably mounted in the intermediate frame plates 22 and is provided with a plurality of laterally spaced, upstanding pins I26 fixed therein. The pins I26 are adapted to enter the open portion between the stop bars H2 and H3 of the digital control bars 6! to maintain proper alignment thereof with respect to the key stems 41. A similar transverse support bar I2! is mounted at the rear of the machine, and formed thereon is a horizontal arm provided at its forward end with a small slotted portion I20 in which is positioned the upper portion of the upright arm I24. The bar I21 is also provided with pins I26 adapted to be embraced by the open potrion of the digital control bars 6I to maintain proper alignment of the rear ends thereof with respect to the key stems 41. The rock shaft I2I and the support bars I25 and I21 and digital control bars 6I are normally maintained in the position of Fig. 9 under tension of a spring I30 (see Fig. 3) interconnected between the lower end of the arm I23 and a frame plate 22 to retain the regular stop bars I I2 in operative relationship with their associated digital key stems.

With such an arrangement, it will be readily perceived that upon depression of the minus control key 86, the resulting movement of arm arms I23 and I24. :;The digital control support bars I25 and I21, will similarly be shifted to position the stop bars I I3 and H3 in operative relationship with the stop portions I9 of the key stems 41. When either of the stop bars H2 or I I3 is in operative relation with the stop portion I9 of the ordinal key stem, the other stop bar is completely out of operative relation therewith. A slot 46 is cut in the lower portion of each of the key stems 41 and is adapted to be in alignment with the stop bars H3 and H3 when the stop bars II2 are in eifective or operative position relative to the key stems 41, as shown in Fig. 9. When the stop bars II3 and H3 are in effective or operative position relative to the key stems 41, then the stop bars IIZ will pass freely by the stop portions I9 at the left of the key stems, as viewed in Fig. 10.

The means for releasing the clutch hooks 58, after the subtrahend has been set up on the keyboard; is under the control of the equals key 81, the stem 88 of which is in engagement with a lever I28, see Fig. 4. Depression of key 81 and lever I28 causes clockwise rotation of pawl 98 disengaging its lower arm 99 from pin I05 of the arm I06 and allowing the shaft I91 to be rocked clockwise under the tension of its spring I60, see Fig. 3. The lock arms I98 are thus removed from looking engagement with lugs III on hooks 58, thereby allowing those hooks in the denominational orders in which digital keys have been depressed in the previous setting of the subtrahend into the keyboard to drop into engagement with their toothed wheels 13.

As has been mentioned, it is necessary that 9's be added in all denominational orders other than the units order, in which no digital key has been depressed, and that 10 be added in the units order if no key has been depressed therein, for the purpose already explained. The lever I28 pivoted on a short shaft I3I is provided with an ward rocking movement of shaft I38 and arms- !99, thereby urging links 55 forwardly. The forward movement of the links 55, through the parallel motion device, causes depression of hooks 58 controlled thereby into the paths of their associated toothed wheels. Movement of the parallel motion device not having resulted from depression of a digital key 24 in such order, the bar 6| which controls the digital setting of the sector gear 42 will receive full forward movement, with a consequent maximum downward movement of the gear sector sufficient to add 9 into the accumulator upon the upstroke of the sector under tension of spring 46. When no key has been depressed in the units order, that is, when a zero occurs in the units order of the subtrahend, forward swinging of the arm I39 therein will likewise cause maximum downward movement of the gear sector 42, but the resultant upstroke by the spring 49 will add 10 into the units order of the accumulator.

To automtaically add 9 to the accumulator mechanism of the overflow order to bring to zero position the numeral wheel of that order when a 1 has been carried thereto by the entering of the complemental value of the subtrahend and the subsequent adding of 9s and carrying of the 1 across the register as just described, a sector 242 is provided, see Fig. 4. The sector 242 is similar to the sectors 42 already described and mounted on the shaft 43, but is directly connected to guide member 266 by link 259, and rearward movement of guide member 260 to move sector 242 downwardly is accomplished through connection with guide member 69 of the next lower denominational order. This connection is effected by depression of minus control key 86 and forward movement of link 255 which, through pin I46 fixed in link 255, causes rocking movement of lever I48 and engagement of lock piece I54 with pin I51 fixed in the guide arm 68. The lock piece I54 is mounted on the guide arm 260, and when hook member 58 engages with toothed wheel 13 of the denominational order to the right of the overflow order, resulting either from setting of a digital key 24 therein and/or depression of the equals key, the guide member 68 in that order will be pulled rearwardl and, by its connection with guide member 299 of the overflow order, the gear sector 242 of the overflow order will be given a maximum downward movement to add 9 upon its upward movement under the action of spring 246.

As the guide member 268 is moved rearwardly as just described the pin 21! located thereon engages and releases the latch 256 from the dog 25? to allow the parallel motion bar 89 to return to its normal raised position and allowing the key 86 to be raised to its normal elevated position.

Means are provided for preventing the relatching in a depressed position of parallel motion bar 89 and minus key 86 if the equals key 81 is allowed to rise while the key 96 is still being held depressed by the operator, or if the equals key 81 is held down by the operator. T this end, there is provided a forwardly extending arm I 59 on latch 256 of the overflow order which is adapted to engage the face of a lip or lug I6I formed at the extremity of a vertical lever I62 (as shown in Fig. 4).- The lever I62 is moved slightly clockwise against the tension of its spring I63 by the arm I59 when parallel motion bar 39 is depressed by the minus key 85, and link 255, to which the latch 266 is pivoted, is moved forwardly. Subsequent operation of the equals control key 81 causes rearward movement of the guide member 269 of the overflow order, as already described, whereupon pin 211 of guide member 266 engages the finger 219 of latch mem- 11 her 266 to swing the latter in a clockwise direction. In such movement of the latch 256, the arm I59 thereof is swung beneath the lip or lug I6I on the lever I62, and the latter is moved rearwardly in a counter-clockwise direction by its spring I63 to maintain the latch 266 in inoperative position. In this position, the downwardly extending arm 2'15 of the latch 25% is to the rear of projection 216 of dog 26?, and the dog cannot be ,relatched in such position until the parallel motion bar 89 has been allowed to return to its upper or normal position and has again been depressed by the minus key 85. Thus the subtractive control devices are compelled to return to normal position after a subtractive operation, and the machine is automatically conditioned for additive operation.

The present invention is more particularly concerned with the provision in such a machine of simplified means for performing division. Heretofore, in machines of the type disclosed, division was performed by a process of repeated addition of the complement of the value of the divisor. For instance, if it were desired that the figure 11,856 be divided by the figure 456,

the former was registered in the numeral wheelsof the accumulator by depression of the keys bearing those figures, and the finger tips were held in contact with the tops of the digit keys representing the complement of the divisor in the denominational orders immediately above the sight apertures in which the figures "185 appeared (the figure 456 being .greater than the figure l18), the means for locating the complement of the divisor on the keyboard consisting of the inscription on the keys of the nines complement of the value thereof in small figures (see Fig. 1A) it being necessary to hold the finger tips in contact with the key tops of the digit keys representing the value of the divisor, less one in the lowest significant order of the divisor, on the small complemental figures of the keys. The keys so held, which correspond to the complement of the divisor, were then repeatedly depressed until the numeral wheel in the order.

next higher than the highest order of the divisor showed a value equal to the number of operations or depressions. If the remainder in the orders into which the complement of the divisor was being entered was greater than the divisor, the repeated depressions were continued until the remainder was less than the divisor, after which the divisor was shifted one order to the right and the process was repeated. By this occurred in orders lower than the lowest si nificant figure of the divisor they were ignored and no key was depressed in those orders. The above rules formulated to meet certain condi=- tions have been a source of much confusion to the operator and as a result in machines of the type disclosed, the performance of negative calculation, such as subtraction and division, has not been as facile as desired.

In the present invention, however, the operator is completely relieved of the responsibility and mental burden of determining the complement of the divisor and locating it upon the keyboard when performing a division operation. This is accomplished by means of a control key which, as will be more fully explained hereafter, upon depression by the operator, conditions the ma chine to automatically add to the dividend the nines complement of any key subsequently dethe units order, and to afitomatically add the process the quotient 26 is registered in the numeral wheels of the accumulator with no re mainder.

However, where the divisor contained the figure 9 in the units order or in the intermediate order or orders of the divisor between two figures of value, and where the divisor contained a cipher (0) in an intermediate order or orders between two figures of value, certain rules had to be followed in order to obtain the correct result. For instance, if a 9 occurred as the highest denominational figure of the divisor or as an intermediate figure between two figures of value, it was ignored and no key was depressed in that order in which the 9 appeared. If, however, the 9 occurred as the units figure of the divisor, the same rule as earlier explained was followed 7 and one less, or the small figure 8 was de pressed. Also, where a cipher or ciphers occurred as an intermediate figure of the divisor between two figures of value, the small cipher entering the divisor.

tens complement of the key depressed in the units order, and to add the respective complement of zero in all orders to the right of the left most or highest order of the divisor where no keys are depressed, except the units order, in which "10 is added if no key is depressed therein. For division operations, the complemental marking of the keys is dispensed with, so there are only the large figures thereon. It will be understood that it is no longer necessary to hold one less than the lowest significant figure of the divisor which has heretofore been necessary in performing division on this type of machine. This is accomplished by automatically adding 9s in all orders to the right of the lowest significant figure of thedivisor except the units order in which 10 is added to cause a carry to take place to add, l in the denominational order in which the lowest significant digit of the divisor is being depressed.

Further, .as will be presently explained, the rules heretofore mentioned in connection with the performance of division when the figure 9 occurred in the units order of intermediate order or orders of the divisor between two figures of value, and where a cipher (0) occurred in an intermediate order or orders of the divisor, have been completely eliminated. In performing division on the machine of the present invention, where the figure 9 occurs in the divisor, the 9 key is depressed, and where a cipher (0) occurs, indicating a lack of values, no key is depressed. Division is accomplished, therefore, without the complemental marking of the keys and without the necessity of holding one less in the lowest significant order of the divisor, and without the necessity of reference to or a knowledge of the rules heretofore mentioned in the two preceding paragraphs, all of which have heretofore been a source of much confusion to the operator.

To perform division on the machine in which the present invention is embodied, it is first necessary to enter the dividend into the register wheels of the accumulator by depression of the keys in the usual manner. The present invention is more particularly concerned with the provision of means for facilitating the performance of division by conditioning the machine to automatically control the digital actuation of the actuating mechanism therein in accordance with the complemental value of the keys depressed in Such means completely eliminate the heretofore dual marking of the pressed in accordance with the rules heretofore mentioned. However, in accordance with the present invention, it is no longer necessary to hold one figure less than the actual value of the units figure of the divisor which has heretofore been necessary. The addition of the extra 1 in the units order of the divisor as it is depressed in the varying lower denominational orders in. performing division is automatically provided for,

and the keys representing the actual figures of the divisor are simultaneously depressed.

The means for cintrolling the operation of the machine in division consists of a division control key 3BI which is located to the left of the ordinal series of keys 24 (Fig. 1) below the subtraction control keys 85, 81. provided with stem 88 and spring 38 to normally maintain it in raised position. The stem 88 of the key 30I is provided with an angular lower portion 302 in engagement with a roll 303 which is rotatably secured to an upright arm I I 9' (view- The arm H9 is rotatably ing Figs. 3, 9 and 10) mounted on the rock shaft I2I which, when rocked as earlier described herein, causes the complemental stop bars I I3 and I I3 to be shifted into operative relationship with the key stems 4'I to control the digital actuation of the actuating tal value of any key subsequently depressed. Rigidly mounted on the rock shaft I ZI is an arm 304, the upper extremity of which is in engagea ment with a pin 305 fixed in the arm I I9. From said construction it will be readily understood that the rock shaft IZI may be rocked in a' counter-clockwise direction. viewing Figs. 9 and '10, to shift the stop bars H3 and H3 to the left when the minus control key 86 is depressed, without effecting movement of the arm which is normally maintained in the position of Fig. 9 under tension of a spring 306.

The arm H9 is provided with a lower down- 'wardly extending portion 301 which terminates in a vertical bifurcated end 308 embracing a groove 309 formed in a transverse shaft til I (Figs. 9 and 10). The shaft 3I I is journaled for lateral movement in bearings 3I2 fixed in the outer -2 frame plates of the machine. and is adapted to be moved to the right against the tension of spring 305 upon depression of the "division control key 30I which, through medium of arm 3M and pin 305, also rocks the shaft I2I to'move the,

complemental stop bars H3 and I I3 into operative relationship with the keys 24.

Mounted on a transordinal shaft 3I3 which i disposed in parallel relationship with the shaft 3 are actuation levers 3I4 which are provided between adjacent denominational orders (see Figs. 2, 3, 9, 10 and 12). The levers 3I4 are provided with vertical arms 3I5 and 3I6 which are joined together by a transverse bail portion 3I'I;

the arm 3H5 being slightly offset to the right,

viewing Fig. 12, so as to be aligned with the arm 3I5 of the lever 3M of the next lower denominational order for a purpose to be presently explained. The levers 3 I4 are normally maintained in the lateral position of Figs. 9 and 12 under the The key 30I is,

mechanism in accordance with the complemen- I I tension of spring 306 which as earlier explained, is connected at one end to the arm H9 which is in communication with the laterally movable shaft 3II through the downwardly extending portion 30'! and bifurcated end 308.

Clinched to the shaft 3| I are shifting arms 322 which are provided with bifurcated rearward portions 323 adapted to embrace the shaft 3I3. An arm 322 is provided between each two levers 3I4 and also on the outside to the left and right of the set of levers 3I4 adjacent the arms 3I5 and 3I6 respectively. In the position of Figs. 9 and 12 the upper extremities of the arms 3I5 and 3I6 are'out of the plan of movement of the pin MI of the link 55. In such position the levers 3I4 are, prevented from rotative movement on the shaft 3I3 by means of a pin 3I8 fixed in the intermediate frame plate 22 which is adapted to enter an aperture 3I9 in the extremity of a horizontal rearward extension 32I (see Fig. 3) formed on the lower end of the vertical arm 3I5.

When the shaft 3II is shifted, to the right viewing Figs. 9 and 10, by depression of division control key 30!, the shifting arms 322 which are clinched to the shaft 3II move with it to cause lateral sliding movement of the levers 3| 4 into the plane of movement of, and engaging relationship with the pins MI in the links 55. In the position of Fig. 10 it will be noted that the aperture 3I9 in the horizontal extension 32I on the arm 3I5 has been freed from engagement with the pin 3 I8 fixed in the intermediate frame plate 22 and the lever SM is then free for rotational movement on the shaft 3I3 as will presently be described. In such position it will be noted that the arm 3I5 is forward of the pin MI while its associated arm 3I0 is rearward of the pin I4I of the next lower denominational order, to the left viewing Fig. 10.. With such an arrangement it will be readily apparent that the forward action given to a link 55 by depression of a key 24 will cause, through the pin I M and arm 3I5, clockwise rotation (viewing Fig. 12) of the lever 3". Through the associated arm 3I0, forward movement is transmitted to the link 55 of the next lower denominational order which movement imparts motion to the associated parallel motion bar to cause depression of the book 58 controlled thereby into the path of its associated toothed wheel I3, which results in an adding actuation in that denominational order. Therefore, as each link 55 is given forward movement ittransmits this motion through the arms 3I5 and 3I6 to the link 55 in the next lower denominational order. Movement of each parallel motion device not having resulted from depression of a digital key 24 in such order, it will be readily apparent that bar (H which controls the digital setting of the gear sector 42 will receive full forward movement, with a consequent maximum downward movement of the gear sector sufficient to add "9 into the accumulator upon the upstroke of the sector under tension of spring 45. In the units 'order also, the gear sector 42'will receive maximum downward movement, but the resultant upstroke by the spring 46 will add 10 into the units order of'the accumulator. Adding of 10 in the units order causes a carry of the tens to take place in every order in which 9 has been automatically added to'the right of the lowest order of the divisor until finally the 1 is carried into the order in which the units figure of the divisor has been added. Thus the depressing of keys corresponding to one less than the actual value of the divisor when the keys are simultaneously depressed in performing division on the instant type of machine has been made unnecessary. p To insure full forward movement of the links 55 despite the cumulatively increasing strain upon the ordinal elements of the series of over lapping actuation levers 3l4, there is provided in association with each yielding clutch 63 a cam portion 325 (Figs. 2 and 3) formed integrally with the center disk of the yielding clutch 63. As earlier mentioned, the link 59 is-articulately connected to the yielding clutch 63 through this center disk. When an ordinal key 24 is depressed the link 55 is moved forwardly as earlier described to permit engagement of the hook 58 with toothed wheel 13 which causes rearward movement of the link 59. As the link 59 is moved rearwardly, the center disk of the yielding clutch 63 to which it is connected is rotated in a clockwise direction, viewing Fig. 2, and the cam portion 325 engages a roll 326 mounted on pivot or stud 56, to which the forward end of link 55 is connected, to positively force forward movement of the link 55 and remove any strain attendant with the function of the overlapping actuation levers 3|4 as earlier described.

Due to the slightly delayed return of the link 55 because of the engagement of the cam 325 with the roll 326, the return of the key under fast operation is also somewhat slower, so means are provided'to prevent re-engagement of latch '66 and dog 61 after disengagement by the pin 11- as earlier described. To this end there are provided latches 321 (Figs. 2, 13 and 14) each having hub portions 328 and being mounted on a transverse shaft 329; Each latch 321 is .provided with an upwardly and rearwardly extending portion 33l and terminates in a horizontal arm 332 which is adapted to underlie the arm 6|] move rearwardly the pin 11 mounted in the arm 18 engages the finger 19 to release the latch 66 from the dog 61. As the pin 11 moves rearwardly in anarc, the horizontal arm 332 is allowed to rise under tension of spring 333 when the finger 19 is moved rearwardly from engagement with the extremity of the horizontal arm 332; When the guide arm 66 and link '59 move forwardly'under the tension of spring 46 after release of the clutch hook from the toothed wheel, the pin 11 is removed from engagement with the finger 19 which is allowed to rotate in a counter-clockwise direction under tension of spring 64 but which contacts the end of the arm 332 and is maintained in released position relative to the dog 61 until the guide arm 60 and the link 59 have reached full forward position. As the guide arm is being rotated clockwise about'its pivot 53 under tension of spring 46 the pin 11 strikes the upper surfaced the arm 332 and cams it downward out of engagement with the finger 19 and the latch 66 is allowed to be rotated to its'normal position ,of Fig. 2. However, as previously explained, the

shelf'1l of lever 12 strikes lug 69 of dog 61 to hold'the dog out of engageable relationship with latch 66 after said latch has returned to its "normal position so that nore-engagement "In Fig. 20 is shown a latch of the latch .and dog is possible if they digit key is prolongedly held in depressed position. Without the latches 321, the latches 66 would re,- engage with dogs 61 after every key stroke, to be released only by the forward motion of the lugs 16 to the dogs 61 out of engagement with the arm 15 of the latch 66 when the dogs 61 are swung counter-clockwise by shelves 11 of levers 12, which would make the rising of the keys too slow for fast operation of the machine.

As has been described, upon depression of the keys representing figures of the divisor when performing division, 9s are automatically added in all denominational orders where no keys are depressed to the right of the left-most order in which a key is depressed. In such automatic actuation of the orders to the right, resistance to forward movement of the link 55 :by actuation levers 314 is present in the springs 64 and 334 of the denominational orders to the .right of the key operated order and it may be possible that the link 55 may be moved forwardly enough to cause latching engagement between latch 66 and dog 61 but not sufficient to result in engagement between the clutch hook 58 and toothed wheel 13,. Means are provided, therefore, for releasing the dog 61 from the latch 66 in any orders in which such a condition exists by operation of the zeroizing crank 335 or depression of a release key 31L Mounted on a stud 336 fixed in the intermediate frame plate 22 toward the rear of the machine is an arm 331, having a pin 338 fixed in the lower portion thereof (Fig. 19). .A'lever 339 is mounted on the pin 338 and extends forwardly and downwardly terminating in a hook 341 in engagement with a notch 342 (Fig. 19) cut in a transordinal shaft 343. At the right hand side of the machine, viewing. Fig. 1, an arm 344 (Fig. 15) is rigidly mounted on the shaft 343 and has pivotally secured to its upper extremity a link 345 which is provided with a slot 346 at its forward end. Disposed within the slot 346 isa stud, 341 which is mounted in the intermediate portion of a depending lever 348 (Fig. 15) which is part of the zeroizing mechanism and adapted "to be rotated in a counter-clockwise direction about its pivot 349 ,when the zeroizing crank 335 is pulled forwardly, or to the right viewing Fig. 15. As the zeroizing crank 335 is pulled forwardly the notched shaft 343 is rotated in aclockwise direction against the tension of spring 340 which is connected to the lower extremity of the arm 344, urging the levers 339, the hooks 34l of which are in engagement with notches 342 (Fig. 19), forwardly and downwardly against the tension of springs 35!.

causing its release from the latch 66 and return 'of the parallel motion device to its normal elevated position.

releasinglever 355 which is provided in the leftmost or highest denominational order of the machine in order to clear certain parts which obstruct and prevent the use of the key-release mechanism of Fig. 19 in that order. The lever 355 is provided with a hub portion 356 and mounted for 'slightlongitudinal movement. in the overflow 

